slave_net_timeout -- The default for the slave_net_timeout setting is 3600,
which is 60 minutes. I've set this to 30.
It also removes a step in resuming replication of "STOP SLAVE; START SLAVE"
master-connect-retry -- The number of seconds the slave thread will sleep before retrying
to connect to the master in case the master goes down or the connection is lost. Default is 60.

****Note that for the default setup, networking for guest OS's is bridged. This means that they will get an IP address on the same network as your host, thus, if you have a DHCP server providing addresses, you will need to ensure that it is configured to give addresses to your guests. You can change to another networking type by editing /etc/xen/xend-config.sxp

$ virt-install
What is the name of your virtual machine? test
How much RAM should be allocated (in megabytes)? 256
What would you like to use as the disk (file path)? /opt/test1
How large would you like the disk (/opt/test1) to be (in gigabytes)? 4
Would you like to enable graphics support? (yes or no) no
What is the install location? /opt/testinst
ERROR: Install media location must be an NFS, HTTP or FTP network install source, or an existing local file/device
What is the install location? http://192.168.50.50/centos52

This information can also be passed as command line options; run with an argument of –help for more details. In particular, kickstart options can be passed with

$ /usr/sbin/virt-install
The following questions about the new guest OS will be presented. This information can also be passed as command line options; run with an argument of --help for more details. In particular, kickstart options can be passed with -x ks=options.
1. What is the name of your virtual machine? This is the label that will identify the guest OS. This label will be used for various xm commands and also appear in virt-manager the Gnome-panel Xen applet. In addition, it will be the name of the /etc/xen/<name> file that stores the guest's configuration information.
2. How much RAM should be allocated (in megabytes)? This is the amount of RAM to be allocated for the guest instance in megabytes (eg, 256). Note that installation with less than 256 megabytes is not recommended.
3. What would you like to use as the disk (path)? The local path and file name of the file to serve as the disk image for the guest (eg, /home/joe/xenbox1). This will be exported as a full disk to your guest.
4. How large would you like the disk to be (in gigabytes)? The size of the virtual disk for the guest (only appears if the file specified above does not already exist). 4.0 gigabytes is a reasonable size for a "default" install
5. Would you like to enable graphics support (yes or no): Should the graphical installer be used?
6. What is the install location? This is the path to a Fedora Core 6 installation tree in the format used by anaconda. NFS, FTP, and HTTP locations are all supported. Examples include:
* nfs:my.nfs.server.com:/path/to/test2/tree/
* http://my.http.server.com/path/to/tree/
* ftp://my.ftp.server.com/path/to/tree
{i} Installation must be a network type. It is not possible to install from a local disk or CDROM. It is possible, however, to set up an installation tree on the host OS and then export it as an NFS share.

The xen config files are usually found under /etc/xen

to restart a console with a mc

$ xm create -c <configfile>

You can connect to the console of any virtual machine by running

$ xm list
$ xm console <yourvmname>

Xen request the VM to shutdown

$ xm shutdown <yourvmname>

On Linux, this goes through the whole shutdown sequence properly, ensuring that the machine is cleanly terminated. If you want an immediate shutdown, use

$ xm destroy yourvm

but make sure the virtual machine is in a safe state first — if you have a text file open and unsaved, for example, it will be lost.

The xm command can also be used to save snapshots of a virtual machine, rather than just switching them off. To do this, use

$ xm save yourvm yourvm.state

That command essentially saves the RAM of the yourvm VM (change yourvm to whatever you called your virtual machine) to a file and then turns off the VM. To restore a saved state, just use

$ xm restore yourvm.state

To display top-like statistics for all running machines:

$ /usr/sbin/xm top

On the virtualization host server, open a terminal and enter

xm delete vm_name

to delete the virtual machine’s reference in xenstore so it is no longer managed.

The configuration files in /etc/xen are in text format and so are easily edited.
For example, if you want to change the number of CPUs a VM sees, look for the vcpus setting.
Note that these are virtual CPUs rather than real ones —
you can set this to 8 and have your guest see eight CPUs, even if your actual machine has just one

Ok so now we have compiled a new kernel (for example 2.6.18-prep) and the grub looks like I’ve added the command of panic=5 (can have panic=* where * is the number of seconds it waits on a panic) at the end this is to reboot the computer in 5 seconds if kernel panics and will boot with default=1 kernel.

Plone is a ready-to-run content management system that is built on the powerful and free Zope application server. Plone is easy to set up, extremely flexible, and provides you with a system for managing web content that is ideal for project groups, communities, web sites, extranets and intranets.

eWeek

* Plone is easy to install. You can install Plone with a a click and run installer, and have a content management system running on your computer in just a few minutes.
* Plone is easy to use. The Plone Team includes usability experts who have made Plone easy and attractive for content managers to add, update, and mantain content.
* Plone is international. The Plone interface has more than 35 translations, and tools exist for managing multilingual content.
* Plone is standard. Plone carefully follows standards for usability and accessibility. Plone pages are compliant with US Section 508, and the W3C’s AAA rating for accessibility.

OSI

* Plone is Open Source. Plone is licensed under the GNU General Public License, the same license used by Linux. This gives you the right to use Plone without a license fee, and to improve upon the product.
* Plone is supported. There are close to a hundred developers in the Plone Development Team around the world, and a multitude of companies that specialize in Plone development and support.
* Plone is extensible. There is a multitude of add-on products for Plone to add new features and content types. In addition, Plone can be scripted using web standard solutions and Open Source languages.
* Plone is technology neutral. Plone can interoperate with most relational database systems, open source and commercial, and runs on a vast array of platforms, including Linux, Windows, Mac OS X, Solaris and BSD.

When I ran this command it gave me an error of /usr/lib/zope/skel not found
So I mkdir -p /usr/lib/zope/skel

You choose this install directory:
Directory: /home/zopy/zinstance/
You must choose a username and password.
Username = admin
Passwd = ******

Now, you run zope
/etc/init.d/zope start

Start a web browser on the same machine on which you installed Zope and visit the URLhttp://localhost:8080/
If your Zope is properly installed and you’re visiting the correct URL, you will be presented with the Zope “QuickStart” screen.

/etc/init.d/zope stop

To add users to zope
zopectl adduser uname passwd

/etc/init.d/zope start

Logging In

To do anything remotely interesting with Zope, you need to use its “management interface”. Zope is completely web-manageable. To log into the Zope management interface, use your web browser to navigate to Zope’s management URL. Assuming you have Zope installed on the same machine from which you are running your web browser, the Zope management URL will behttp://localhost:8080/manage or http://192.X.X.X:8080/manage

Add Plone Site
Enter an ID and click the button below to create a new Plone site.
Id
Plone
Title
Portal Of Plone
Membership source
XXXXX
Description
Any Thing You Like
Button –> Add Plone Site <– Button

In general, many new Linux System Administrators create only two partitions / (root) and swap for entire hard drive. This is really a bad idea. You always need to consider following points:
-Performance
-Security
-Stability
-Backup

Let us assume you have 120 GB SCSI hard disk with / and swap partitions only. Then here comes a user (may be internal or external or cracker user) and runs something which eats up all hard disk (DoS attack). For example, consider the following tiny script that such user can run in /tmp directory:

#!/bin/sh
man bash > $(mktemp)
$0

Anyone can run above script via cron (if allowed), or even with nohup command:
$nohup bad-script&
Result is disaster! Your entire file system comes under Denial of Service attack. It will even bypass the disk quota restriction. A Linux sys admin created only two partition. Later, poorly written application eats up all space in /var/log/. End result was memo for him as he did not followed internal docs that has guidelines for partition setup for clients server.

If you don’t have partitions like this then following attack can take place:
1. Denial of Service attack against disk space (example is the script above)
2. Users can download or compile SUID programs in /tmp or even in /home
3. Performance tunning is not possible

However, all of this attack can be stopped by adding following option to /etc/fstab file:
nosuid – Do not set SUID/SGID access on this partition
nodev – Do not character or special devices on this partition.
noexec – Do not set execution of any binaries on this partition
ro – Mount file system as readonly
quota – Enable disk quota
Please note that above options can be set only if you have separate partitions. Make sure you create partition as above with special option set on each partition
/home – Set option nosuid, and nodev with diskquota option
/usr – Set option nodev
/tmp – Set option nodev, nosuid, noexec option must be enabled

Apply the Secure Linux Kernel Patch http://www.openwall.com/linux. Read the directions to install the diff.
Don’t forget to make the changes under performance
Turn OFF all the stuff you don’t need. This includes Telnet (you aren’t using telnet are you), NFS and a bunch of other crap that comes as a default install.
Stop SYN attacks dead :
echo 1 > /proc/sys/net/ipv4/tcp_syncookies.
Add this to your /etc/rc.d/rc.local file.
Stop IP address spoofing: Edit the /etc/host.conf and add the following lines:
#Check for IP address spoofing.
nospoof on
Set immutable bits on passwords and shadow files. Of course you will have unset these bits to change passwords etc, so do this after your system is stable.
Block su access: Edit /etc/pam.d/su and add the following two lines to the top in the file:
auth sufficient /lib/security/pam_rootok.so debug
auth required /lib/security/pam_wheel.so group=wheel
This means that only users in the wheel group can log as su.
Add who you need to this group:
usermod -G10 username
I changed my /etc/fstab as follows
/dev/sda5 /tmp ext2 nosuid,nodev,noexec 1 2
This was to make /tmp safer, Of course your /dev will be different.
I don’t like having my shell commands living forever. (of course this doesn’t matter if noone has ssh access but you) (you are using ssh, if not you don’t have security).
Edit /etc/profile and change the following line to:
HISTFILESIZE=20
Change permissions on /etc/rc.d/init.d scripts:
chmod -R 700 /etc/rc.d/init.d/
Edit the /etc/nsswitch.conf file to eliminate all references to NIS. Why would you use NIS unless recquired?

use strict;
use Crypt::PasswdMD5;
# This will ask you for a password once all users will have the same passwd
print “Enter Password: “;
chomp ( my $Passwd = );
$cryptedPasswd = unix_md5_crypt($Passwd, $salt);